This invention relates to a propulsion system suspension for a railway truck and, more specifically, to such a suspension system which includes means for universally coupling the gear box and the traction motor of the propulsion system thereof.
Modern railway transit cars must be comfortable, durable and reliable for the safety and convenience of the passengers travelling thereon. A number of railway trucks such as those disclosed in U.S. Pat. Nos. 3,313,245 and 3,646,893 include means for allowing some independent side frame action which does contribute significantly to a smooth and comfortable ride. However, the relative movement of the side frames does complicate propulsion system suspension.
One type of propulsion system, which has heretofore been used in railway trucks utilizes a traction motor which is generally mounted to be parallel with the axle. One conventional configuration having this parallel drive arrangement includes a gear box through which drive is imparted to the axle by the electric traction motor which was rigidly mounted to the gear box. Since the traction motor and the gear box unit form a rigid assembly, the entire assembly is resiliently mounted to the axle and the truck side frames. The output means of the gear box includes a main gear drivingly secured to a quill shaft which is fitted about the truck axle and utilizes a resilient means for the actual connection with the truck axle. The torque reaction of the driven axle is taken by a vertical linkage or torque arm connected resiliently between the gear box-motor configuration and the truck frame. Such prior arrangements had the advantage of a compact drive assembly but introduced some structural and maintenance problems. The resilient connection between the gear box-motor configuration and the truck frame has to be sufficiently strong to support the weight of both and generally has to be limited to only one of the side frames when the truck is designed to allow a significant amount of relative movement between the side frames. Additionally, should problems develop with the resilient coupling between the gear box and the truck axle which require its replacement, repairs would be quite difficult since a complete disassembly of the axle and wheels would be required.
U.S. Pat. No. 3,468,389 discloses a propulsion system configuration which was intended to eliminate some of these problems. In this configuration, the output gear of the gear box is rigidly secured to the truck axle while its input end is resiliently coupled to one of the side frames. The traction motor includes a rear end which is resiliently secured to the other side frame and extends transversely to be joined to the input end of the gear box. However, rather than being solidly coupled to the input end of the gear box, the front end of the traction motor is resiliently coupled thereto. This configuration does eliminate the need for supporting the entire gear box-motor configuration from one side of the frame and for including a resilient coupling at the axle. It neverless relies on another resilient coupling means, one which is between the motor and the gear box and is subject to failure. Further, resiliently coupling the motor to the input end of the gear box requires that the actual coupling of the motor shaft and the gear box input shaft must also be resilient.